Been using the pull out method for a year now?

I stopped taking birth control awhile back, and my boyfriend and I never really use condoms anymore. We've been using the pull out method for a year now and I'm surprised I haven't gotten pregnant yet. I don't want a baby right now but It wouldn't be the end of the world if I did fall pregnant ( I'm not underage, and can support a baby ) Just want to focus on college right now. So basically my question is why haven't I gotten pregnant yet? Does this " method " really work? Is it luck? Or could there be something wrong with me? Thanks in advance! :P